1. Field of the Invention
This invention is directed to filtering systems. In particular, this invention directs itself to a stepped plenum system wherein particulate laden gas may be equally passed to a plurality of filter bags within a baghouse compartment. Still further, this invention pertains to a stepped plenum system whereby particulate laden gas may be equally distributed in both flow rate and pressure drop conditions in a substantially equal manner to a multiplicity of filter bag systems. More in particular, this invention directs itself to a stepped plenum system wherein there is provided an inlet conduit having a plurality of outlet conduits in fluid communication with the inlet conduit. More in particular, outlet conduits are arranged in a longitudinally displaced manner each with respect to the other and defining stepped flow regions wherein a portion of the inlet gas is diverted from the inlet conduit to the outlet conduits in a stepped manner. Further, this invention relates to a stepped plenum system wherein there are provided a plurality of outlet conduits in fluid communication with an inlet conduit having a multiplicity of vane members at the inlet and outlet sections of the outlet conduits to provide for even distribution and patterning of gaseous flow passing therethrough.
2. Prior Art
Filtering systems using fabric filter bags for filtering particulate matter from gaseous streams is well-known in the art. Additionally, systems have been developed to try to equalize the flow rate and pressure drops through the filter bags in baghouses. However, the prior flow equalizing systems have not been overly effective resulting in serially connected filter bags having differing flow rates as well as differing pressure drops therethrough. Such has resulted in different filter bags accomodating more of the flow rate and having a resulting lower lifetime than other filter bags in an overall system. This has resulted in unscheduled and unwanted replacing of some filter bags in an overall system while other filter bags are essentially still operational. Thus, deleterious effects result from down time of the operational system and increases the labor costs associated with the replacement of certain filter bags in an overall system at unscheduled times. The equalization of flow rate has been seen as a major cost of operation of filtering systems of the filter bag type.
Previous attempts to equalize the flow rate has been directed generally to utilizing a tapering inlet duct system. However, it has been found that in tapered design systems, poor flow patterns are found due to the unvaned turn from a tapered plenum to individual modules. Such flow patterns have been found to cause vortices as such enter hopper areas of the filtering systems and such increase both mechanical pressure losses and also provides a potential for erosion of the fabric at the bottoms of the filter bags.
The closest prior art known to Applicants include the following U.S. Pat. Nos.: 1,816,064; 2,370,444; 2,439,850; 2,904,130; 2,717,054; 3,543,931; 2,768,744; 2,209,339; 2,866,518; 2,995,207; 2,867,290; 2,696,895; and, 2,433,774.
U.S. Pat. Nos. 1,816,064 is directed to a filtering system, and there are provided lengths of the filtering elements in a somewhat stepped type configuration. The air to be cleaned is emitted at a lower end of the tubular filtering elements which are seen to be mounted in stepped relation within the housing, however, such does not provide a stepped type inlet and outlet duct system, as is provided in the subject invention concept.
Reference U.S. Pat. No. 2,439,850 is directed to a system which is used in the manufacturing of carbon black. They do provide a main duct which leads from the source of the suspension to be separated with ducts coupled to the main duct in a somewhat stepped relation for entrance into respective separator units. However, once again, there is not provided the stepped type pattern between inlet and outlet ducts, as shown in the subject invention concept for the flow pattern equalization as provided.